Pre-treating raw tobacco



Nov. 8, 1960 N. DOCK FEE-TREATING RAW TOBACCO Filed Jan. 6, 1958 UnitedStates Patent 2359470 PRE-TREATING RAW TOBACCO Nils Dock, Bromma,Sweden, assignor'to Aktiebolaget The present invention relates to amethod and apparatus for pre-treating raw tobacco packed in cases orbales for storage in the manufacture of cigarettes.

In the manufacture of cigarettes or similar tobacco products it iscommon to mix raw-tobacco of a great number of varieties. Although themanufacturing capacity is relatively great, the consumption of eachseparate variety of tobacco will thus be considerably smaller. Rawtobacco from U.S.A. is, for instance, as a rule packed in barrel-shapedcases containing about 450 kg. Each separate portion from such a casewill often be as small as kg. In order to prevent the tobacco from beingunnecessarily crushed during this portioning the case must first bemoistened. Such moistening is usually carried out by means of vapor,which will give the whole case a temperature of 60-70 C. During thefollowing relatively rapid cooling which may occur during 3-5 hours inan open space the tobacco unavoidably loses part of its moisture andfurthermore there is a risk that the tobacco will become discolored andwill deteriorate in taste. There has, therefore, for a long time been ademand for a new method of loosening and storing the whole case directlyafter its moistening for future portionings. The present inventionrelates to a new and improved method of loosening the contents of thewhole tobacco cases for the subsequent storing lot by lot in openstorage spaces for the continuous manufacturing process which spaces aresituated in or adjacent the manufacturing room proper. From said spacesthe loosened tobacco in portioned in a usual manner according to thetobacco recipe for the brand being manufactured. Because of this newmethod, the tobacco will not lose any moisture or be subject to anyquality deterioration regardless of the length of the storing time.

The method according to the invention is mainly characterized in thatthe raw-tobacco in unbroken packing units is humidified andsimultaneously heated by being treated in an atmosphere saturated withvapor. The bulk then being mechanically loosened and by means of aninjector introduced into a pneumatic transport system operating withcold air saturated with moisture, and further in that said tobacco istransported in serpentine shaped passages for simultaneously cooling andloosening same, the loosened tobacco then being separated in a knownmanner and directly transferred to said storage space. The total timenecessary for the cooling and loosening only amounts to a few seconds.

The transporting air can after the separation of the tobacco suitably becleansed and after re-conditioning be recirculated in said pneumatictransport system.

The invention involves a number of other advantages besides theadvantages of enabling storage with maintained quality. As the tobaccoafter treatment in accordance with the invention during its entirestoring time maintains its loose condition, it will be easier to weighmore exactly and without any substantial waste th: necessary portions ofthe various varieties of a certain mixture.

The invention will now be described more in detail with reference to theaccompanying drawing, illustrating an apparatus suitable for theperformance of the method. {51111 the drawing, 1a designates a devicefor the moisteninggof rawtobacco by means of vapour andsimultaneously'heating the tobacco to atemperature of 60-70? C. Duringthis treatment the raw-tobacco is in its original compact bulk form.After this treatment the tobacco is loosened either manually or by meansof a mechanical disintegrator, in the drawing designated 1b. After itsloosening, the tobacco is transported by means of a suitable transportdevice 10 to a feeding injector 1d, by means of which the tobacco isintroduced into a pneumatic transport system operating with saturatedcold air. The tobacco is during its transport caused to pass inserpentine shaped passages 2 for simultaneously cooling and finallyloosening the same. Owing to the shape of the passages and a choice of asuitable proportion between the quantity of tobacco and the quantity oftransporting air a complete loosening and a rapid and effective coolingof the tobacco is obtained. The time necessary for this part of thetreatment will only be a few seconds. From a precipitation chamber 3,where the tobacco is separated from the transporting air, the tobacco bymeans of a sluicing device 4 is fed to the open storing space 5,intended for the tobacco variety being treated for the purpose ofstoring and subsequent use in the continuous manufacturing process.After separation from the tobacco the transporting air is in theillustrated embodiment passed by a duct 6 to a transporting ventilatoror fan 7 to be recirculated in said pneumatic transport system. 8designates a cooling device for said recirculated air and the device isequipped with spraying means for the supply of a cooling medium, whichis supplied through a pipe 9. The cooled and moistened air is thereafterpassed to a dynamic separator 10 of cyclone type for separating of a fogof liquid particles and dust particles, if any. 11 designates a duct forthe discharge of the cooling medium and separated dust. The air beingcleansed in the separator 10 is discharged through the outlet 12 and ispassed through a connecting duct 13 back to the feeding injector 1d.

Instead of the shown recirculation of the transporting air, said air maybe discharged to the atmosphere after the separation of the tobacco, andfresh transporting air may be supplied to the transporting ventilator orfan 7. In the illustrated embodiment, the elements 8 and 10 may be ofthe design disclosed in US. Patent No. 2,883,167, granted April 24,1959, to Evert Krantz and US. Patent No. 2,881,858, granted April 14,1959, to Evert Krantz et al., owned by the assignee of the presentapplication, or they may be of any other standard design withoutdeparting from the scope of the invention as defined in the appendedclaim.

What I claim is:

In the manufacture of cigarettes, the process of conditioning rawtobacco packed in cases or bales for storage in moist condition andloose form comprising the steps of humidifying and simultaneouslyheating the raw tobacco in said cases or bales by a heated atmospheresaturated with vapor to moisten and heat the tobacco, mechanicallyremoving the tobacco from the cases or bales and mechanically looseningthe bulk to form clumps of heated moist tobacco, continuouslyintroducing the clumps of tobacco into a stream of cold air saturatedwith moisture, causing said stream to flow in serpentine-shaped paths toeffect loosening of said clumps simultaneously with cooling andtransportation of said moist tobacco without moisture loss, andseparating the cooled Patented Nov. 8, 1960,

2,959,176 3 r 3 and loosened moist tobacco from said stream and direct-FOREIGN PATENTS 1y transferring the tobacco to the storage space incool,

158,380 Sweden Mar. 26, 1957 mOlst and loose condition. 177,363 AustriaJan. 25, 1954 V r 5 ,061 G ....n References Cited in the file of thispatent 5 39 ermany 1931 UNITED STATES PATENTS OTHER, REFERENQES Drylngand Processing of Materials by Means of 3 BllellSOd 29, 1925 ConditionedAir, Air-Carrier Engineering Corp., pages 1,832,119 Hohn et a1. N 17,1931 103-104, published 1929 by Carrier Engineering Corpo- '2,467,248Arelt Apr. 12,, 19 9, 10 ration, Newark, NJ.

